1. Field of the Invention
The present invention relates to a method for manufacturing printed wiring substrates, a metal plate for use in manufacturing printed wiring substrates, and a multi-printed wiring-substrate panel.
2. Description of the Prior Art
Conventionally, there is known a printed wiring substrate configured such that resin dielectric layers and wiring layers are formed on opposite sides of a metal plate, which serves as a core, or so-called metal core substrate, (refer to Japanese Patent Application Laid-Open (kokai) No. 2000-101245). A printed wiring substrate of this kind is manufactured by, for example, the following method. First, resin dielectric layers are formed on the opposite sides of the metal plate. Then, wiring layers are formed on the corresponding resin dielectric layers by means of etching or the like, thereby forming a multi-printed wiring-substrate panel, which is configured such that a plurality of printed wiring substrates are integrally arranged on the same plane. Next, the multi-printed wiring-substrate panel is diced along predetermined cutting lines into discrete printed wiring substrates. This method is called a “multi-piece fabrication”.
As compared with an ordinary printed wiring substrate that is manufactured by use of a copper clad laminate, a metal core substrate of the above-mentioned configuration includes a considerably thick metal portion (mainly a core portion). In recent years, a thickness in excess of 100 μm is becoming dominant. Thus, in dicing a multi-printed wiring-substrate panel into discrete printed wiring substrates, an ordinary dicing apparatus bears a considerably heavy load and thus encounters difficulty in dicing.
If, in order to reduce the amount of the insulating resin material which is trapped in the half-etched grooves, for example, the half-etched grooves are merely shallowed, readiness of cutting will be impaired, thereby failing to enhance productivity as intended.
The present invention has been achieved in view of the foregoing and an object of the invention is to provide a method for manufacturing printed wiring substrates which can manufacture printed wiring substrates each having resin dielectric layers of uniform thickness and excellent surface flatness while maintaining favorable cutting performance in a dicing step; a metal plate for use in manufacturing printed wiring substrates; and a multi-printed wiring-substrate panel.